X-ray tube.



H. P. WAITB.

1 X-RAY TUBE. APPLIoATIoN FILED 1111.25, 190e. RENBWED MAY 1a, 1910.

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Patented J an. 24, 1911.

vwentoz SH01/wup UNITED n' sTATEs PATENT 'oEEIcE `HARRY F. WAITE, OF NEWYORK, N. Y.

I t y x-EAY TUBE.

Specification of Letters Patent.

`Application led January 25, 1906, Serial No. 297,834; Renewed May 13,1910. Serial No. 561,174.

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To all/whomy 'it that I, HARRY F. WAITE, a

Be it known citizen of the United States, and resident of ings zFigure 1is a view o the city, county, and State of New York, have inventedAcertain new and useful Imrovements in X-Ray Tubes, of which theollowing is a specification.

My invention relates to improvements 1n Roentgen or X-ray tubes, and hasfor its object to improve the construction, arrangement and operation ofsuch tubes, and to' these ends my invention consists in a tube embod ingthe features of construction arrange and operating substantiall in themanner hereinafter more partie arly set forth.

Referring to the accom anying drawan X-ray tube embodying my invention,and Fig. 2 is a modification.

In the operation of an X-ray tube or bulb of the ordinary character,especially ywhen it lis connected to X-ray coils as a source .of

energy, it is found that there is more or less inverse current, that is,a part of the time the poles are reversed so that what is ordinarily theanode becomes the cathode and the cathode becomes the anode. When thecurrent is iiowin'g inthe proper direction the cathode stream from thecathode cup strikes upon the target, generating the Roentgen or X-raysin the manner well understood. lVhen, however, the current is reversed,as happens in an alternating current machine, the target becomes thenegative or cathode and the cup becomes the anode, and the cathode raysstream from the target and strike upon the body of the tube, andbombarding this part of the tube, produce or generate X-rays at thispoint.

The target T is usually made of metal, and I have found that when X-raysare generated by the cathode stream striking the body of the tube orbulb whichisof glass, the are of a different quality from those Vwhichare generated when the cathode kstream strikes the target T, and thischange in the quality of the rays interferes with the use thereof,especially when the X-rays are used in making photographic plates.

the quality or character of the rays gener ated when the cathodestreamim inges upon the target or the body of the tu e 1s eliminated. l v

One form of my invention is shown in Fig. 1, wherein R re resents themain tube o bulb, and forme tube Ris what may be termed an interior orsecondary tube E. This tube may be mechanically produced in various waysknown Patented Jan. 24, 1911.

in. or connected with the to those skllled in glass working, and theyneed not to be described specifically herein. This secondary tube isarranged so that it may be subjected to the same degree of exhaustion asthe interior of the main or primary tube R, and a simple way to insurethis is to provide the secondary tube with an opening D. This interioror secondary tube is made of some material which is opaque to X-'rays,as for instance, it may be made of or secondary tube is arran edasecondary target G which is preferab y of metal, and also arranofedthereln is the anode A which is adapted to be connected to the positiveterminal B of the g-rav coil or other source of energy. The cathode ornegative terminal C is shown preferabl provided with a cup-shaped diskC', and t e target T, which is preferably of metal, is shown as having aflat surface and supported by a.bar extending into a neck A.

In operation, the terminal B is connected to the positive terminal ofthe source and the terminal C to the negative terminal of lead glass,and mounted within the interior Y the source. A. will thus be the anodeand understood. If, however, there is a reversal of current, then Cbecomes the anode and A the cathode. lThe cathode stream from A willimpin e upon the secondary target Gr, producing -rays. The direction ofthis X-rays is, however, away from the X-ray plate that would be exposedand away from the operator using afluorosco e, and 1n addition the leadglass wall of t e tube E will effectively cut oif 'any X-raysgenerated.V Since the cathode stream is rectilinear and entirely cut oftby the target -or screen G, target T will be in the shadow and thecathode rays will not im inge upon it. At this time, that is, when isthe anode and A.

vthe cathode, the target T is entirel visolated and does not form a`cathode as is t e case in the ordinarytube. When, however, A is theanode and Cthe cathode, then -no X- Y rays will be produced at G, butonly. at T. While X-rays would be generated at, the secondary target G,their direction is awa from the X-ray plate that would be expose 0rwould be away from the operator using a fluoroscope. In the ordinaryoperation of the tube however if there is no reverse current then therewill be no X-ray generated at the secondary target, all of the X-raysbeing generated at the target T.

It will thus be seen that artube constructed on the general principlesabove set forth, that is, providing the main tube or bulb with asecondary tube which is opaque to X-rays, and generating the X-raystherein, a simple means .is 'provided' for overcoming the disadvantagesinherent in the ordinary X-ray tube whenever reversals of the currentvor changes of direction of the stream of cathode rays take place.

In Fig. 2 I have shown a similar embodiment of my inventionexcept thatthe sec--- ondary tube is external to the main bulb or tube the partsbeing otherwise arranged sub,-

. stantially as shown in Fig. 1, and being similarly lettered.

While I have shown several embodiments of my invention, it is evident tothose skilled in the art that the principles thereof may be otherwiseembodied without departing from the spirit of theinvention, and thedetailsI of construction of X-ray tubes em bodying the invention areimmaterial.

l. *An X-ray bulb'comprising a main tube and a secondary tube opaque toX-rays and 40 communicating with the interior oi the main tube, a maintarget mounted 1n said mam tube and a secondary target mounted in said lsecondary tube, and electrodes.

2. An X-ray bulb comprising a main and secondary tube, a target mountedin the vided with one of the electrodes and with a target, and anotherelectrode.

4. An X-ray bulb comprising a main tube and a secondary tube, the latterbeingopaque to X-rays, one of the electrodes being located in thesecondary tube and the other being located in the main tube, and twotargets one of which is located Within the sccondary tube.

5. In an X-ray apparatus, a bulb provided with a target and a pair ofelectrodes, and a screen between one of the electrodes and the target.

6. In an X-ray apparatus, a bulbcomprising a main tube, and acommunicating secondary tube formed of a material opaque to X-rays, atarget and an electrode in the main tube, an electrode in the secondarytube, and a screen in the secondary tube positioned to cut off thecathode rays which proceed from the electrode in the secondary tube.

In testimony whereof I aiix my signature in presence of two witnesses.

HARRY F. WAITE. Witnesses:

HENRY E. WAITE, CHARLES KALLMEYER.

